"If an item comes into the British Library and it is protected by DRM, it makes it very hard for us to ensure long-term access to that copy," said Dr Clive Field, director of scholarships and collections at the British Library.

As a copyright library, the British Library has a responsibility to keep a copy of everything published in the UK. And like all libraries, it must be able to allow members of the public to duplicate parts of the material in its care. But the Library is finding that in the modern age much of the material it collects comes in electronic form.

"These days a journal, such as The Lancet, will come electronically, and with restrictions that are greater than we get with a print version," said Ben White, copyright and compliance manager at the British Library.

APIG is investigating DRM following the saga of the Sony BMGrootkit. Last year, Sony shipped music CDs which contained copy-restriction software that used rootkit-like technology to hide itself. This opened up a user's PC to attack, led to heavy criticism and put Sony BMG on the receiving end of a number of lawsuits.

Thursday's hearing also included contributions from the Open Rights Group and the Foundation for a Free Information Infrastructure. Both groups expressed strong opposition to DRM.

"DRM has many problems," said Suw Charman, executive director of the Open Rights Group, which campaigns against legislation that threatens users' digital rights. "DRM can't distinguish between lawful and unlawful behaviour, and it contains all the information needed to crack it. It just takes one person to crack a DRM technology and it is obsolete."

Charman cited the Sony rootkit as evidence that DRM can cause serious damage, and pointed out that most UK consumers don't realise that under copyright law they don't have the right to copy music between devices for personal use.

"DRM limits the ability to enjoy legally purchased material, and punishes behaviour widely seen as normal. It will simply criminalise more people, but do nothing to change behaviour, because people will still think it's fair and reasonable," Charman said.

One MP pointed out that virtually all media companies use digital rights management in some form, but Rufus Pollock, UK director of the FFII, argued that this didn't prove that DRM was a good thing.

"Content developers are pretty terrible at predicting which technology breakthroughs would be good for them," said Pollock.

The Royal National Institute for the Blind (RNIB) gave APIG a clear example of where DRM is going wrong. Lynn Holdsworth, a visually impaired member of the RNIB Web management team, told the MPs that she had bought an e-book from Amazon only to find that its DRM would not work with software she uses to make her computer read aloud. "Amazon refused to give me my money back and told me to speak to the e-book publisher, but the publisher pushed the problem back to Amazon. In the end I had to go onto a file-sharing network to find a copy without the DRM, so I could get the material I had the rights to anyway," said Holdsworth.

APIG also heard from rights owners who argued that DRM technology was an essential and valuable part of today's technology and media landscape.

"The current regulatory regime covering DRM is adequate. But we do recognise that a debate is necessary, as this is very early days," said Steve Redmond, director of communications at the BPI, which represents music labels.

"Just to say DRM is good or bad is like saying Internet is good or bad, or computers, or food mixers," Redmond added.

But concerns were also raised about the lifespan of a DRM system.

"Once DRM becomes technologically obsolete, access to the material is lost," warned Dr Clive Field of the British Library. His colleague, Sean Martin, told the MPs that he had encountered a DRM system with a three-year lifespan. "After three years, no-one would be able to access that material," said Martin.